The main thrust of the research conducted by the Crozer-Chester Medical Center (CCMC) neuropsychology service is to investigate the cognitive and neuropsychological differences between patients with a variety of dementing disorders, such as Alzheimer's disease, ischaemic vascular dementia, and Parkinson's disease. Although the issue of differential diagnosis is certainly an important factor in this research, the primary goal is to investigate the cognitive neuropsychological differences between these patient groups. On the basis of Dr. Libon's neuropsychological research, various patient groups have been dissociated on the basis of their performance of tests of motor functioning, frontal lobe functioning, semantic knowledge, visuoconstruction, declarative memory, and procedural memory. The collaborative work being undertaken with Drexel seeks to develop quantitative indices derived from MRI scans of the brain obtained from patients and relate this information directly to the clinical and neuropsychological information that is also obtained on all patients.